1. Field of the Invention
The instant disclosure relates to a feedback control circuit; in particular, to a feedback control circuit that can automatically adjust the timing for turning on or off switches in a switching regulating circuit.
2. Description of Related Art
Usually, in order to improve the efficiency of a switch regulator when it works in the light loading mode, a lower-bridge switch of the switch regulator will be turned off when the inductive current decreases to zero, such that the switch regulator will be in a Discontinuous Conduction Mode (DCM). Commonly, a comparator is used to determine whether the inductive current decreases to zero. However, it is often hard to precisely determine the timing when the inductive current decreases to zero because of an offset voltage of the comparator. As a result, a lower-bridge switch of the switch regulator may be turned off before or after the inductive current decreases to zero, which decreases the overall circuit efficiency of the switch regulator.